The potential of N-acetylcysteine (a free radical scavenger) and ICRF-187 ((plus/minus)-1,2-bis(3,5-dioxopiperazinyl-1-yl) propane), alone and in combination, to protect against chronic doxorubicin cardiotoxicity was examined in the beagle dog model. This cardiotoxicity was prevented by pretreatment of the animals with ICRF-187, but not by pretreatment with N-acetylcysteine.